CPT code 80199: Tiagabine level, quantitative drug assay2026 Medicare lab fee · Clinical Laboratory Fee Schedule
CPT 80199 reports a laboratory measurement of tiagabine concentration, distinguishing it from assays for other medications in the therapeutic drug-monitoring code series.
Medicare pays $27.11 for 80199 under the 2026 Clinical Laboratory Fee Schedule: one national amount, the same in every state and setting.
Medicare lab fee · CLFS 2026 Q4
National CLFS amount
$27.11
In effect since Jan 1, 2026. The same amount in every state, payment locality and setting.
- Geographic adjustment
- None
- Office vs facility
- Same
- Since 2020
- Unchanged
- CMS updates
- Quarterly
Medicare pays the lesser of the lab’s charge and this amount. Patients usually owe no Part B deductible or coinsurance for covered clinical lab tests.
On this page 8 sections
What 80199 covers
80199 identifies a laboratory measurement of tiagabine concentration. It is a drug-specific quantitative assay: the result represents the tiagabine level, not a measurement of another medication such as lamotrigine or levetiracetam. A clinical laboratory performs the analysis and reports the result for the ordering clinician. The code applies when the laboratory assay measures tiagabine.
Report 80199 for the tiagabine assay. Medicare pays this test only through the CLFS; it is excluded from the physician fee schedule by statute. The 2026 national CLFS amount is $27.11 and has remained unchanged since 2020. The CLFS sets one national amount per code, with no geographic adjustment or office-versus-facility difference; the same amount applies across states and localities.
This summary was written with AI assistance from CMS Clinical Laboratory Fee Schedule data. Amounts on this page come directly from CMS files.
How Medicare pays 80199
Clinical lab tests aren’t priced like physician services. They’re paid from their own fee schedule, with its own rules. See the whole lab fee schedule.
One national amount
CMS sets a single Clinical Laboratory Fee Schedule amount for 80199. There’s no geographic (GPCI) adjustment, so it pays the same in every state and payment locality.
No office or facility rate
Lab tests aren’t built from relative value units, so there’s no office and facility split: the place of service doesn’t change the CLFS amount.
Updated every quarter
CMS republishes the CLFS each quarter. New tests, often proprietary laboratory analyses (PLA codes), join during the year; existing amounts are updated each January.
Excluded from the physician fee schedule
The physician fee schedule lists 80199 with status X (excluded by statute), so the test itself is paid only from the CLFS.
80199 on the lab fee schedule since 2020
80199 · CLFS 2026 Q4 (current)
$27.11
Unchanged since Jan 1, 2020
27 quarterly CLFS releases on file, first CLFS 2020 Q1. A code missing from a quarter wasn’t on that release.
80199 compared with similar tests
- 80175Lamotrigine levelQuantitative drug assay$13.25
- 80175 measures lamotrigine; use 80199 when the laboratory measures tiagabine.
- 80177Levetiracetam levelQuantitative concentration$13.25
- 80177 measures levetiracetam rather than tiagabine. Select the code for the medication tested.
- 80183Oxcarbazepine levelQuantitative concentration assay$13.25
- 80183 measures oxcarbazepine; 80199 identifies the tiagabine assay.
80199 billing questions
What does 80199 measure?
It reports a quantitative measurement of tiagabine concentration. The code identifies the medication assayed.
How is 80199 different from 80175?
80199 measures tiagabine; 80175 measures lamotrigine. Select the code for the medication the laboratory measures.
How is 80199 different from 80177?
80199 identifies the tiagabine assay, while 80177 identifies the levetiracetam assay.
How does Medicare pay for 80199?
Medicare pays 80199 through the CLFS. The code is excluded from the physician fee schedule, and the CLFS amount is the same across localities and office and facility settings.
Where this amount comes from
FeeBase reads lab amounts directly from the CMS Clinical Laboratory Fee Schedule file for the quarter: one row per code, with its payment indicator and national amount. Contractor-priced tests are labeled, never given a made-up amount. Amounts are Medicare payment limits, not a patient’s bill or a commercial rate.
CMS CLFS 2026 Q4 · effective Oct 1, 2026 through the day before Jan 1, 2027
Show the CMS file line behind this amount
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